U.S. patent application number 12/912324 was filed with the patent office on 2012-04-26 for system, method and apparatus for storage architecture for bit patterned media using both erase band and shingled magnetic recording.
This patent application is currently assigned to Hitachi Global Storage Technologies Netherlands B.V.. Invention is credited to Michael K. Grobis, Hans J. Richter.
Application Number | 20120099216 12/912324 |
Document ID | / |
Family ID | 45972842 |
Filed Date | 2012-04-26 |
United States Patent
Application |
20120099216 |
Kind Code |
A1 |
Grobis; Michael K. ; et
al. |
April 26, 2012 |
SYSTEM, METHOD AND APPARATUS FOR STORAGE ARCHITECTURE FOR BIT
PATTERNED MEDIA USING BOTH ERASE BAND AND SHINGLED MAGNETIC
RECORDING
Abstract
Storage architecture for bit patterned media uses both erase
band and shingled magnetic recording. A hard disk drive may
comprise a disk having bit patterned media with a plurality of data
tracks arrayed in architecture pages having at least one of erase
band mode (EBM), shingled mode (SM) and unallocated space. An
actuator has a head for writing data to the data tracks of the bit
patterned media. A control system monitors, reallocates and
reconfigures the architecture pages from EBM, SM or unallocated
space to a different one of EBM, SM or unallocated space to enhance
performance of the hard disk drive.
Inventors: |
Grobis; Michael K.; (San
Jose, CA) ; Richter; Hans J.; (Palo Alto,
CA) |
Assignee: |
Hitachi Global Storage Technologies
Netherlands B.V.
Amsterdam
NL
|
Family ID: |
45972842 |
Appl. No.: |
12/912324 |
Filed: |
October 26, 2010 |
Current U.S.
Class: |
360/39 ; 360/71;
G9B/15.021; G9B/5.033 |
Current CPC
Class: |
G11B 2020/1294 20130101;
G11B 5/746 20130101; G11B 5/012 20130101; G11B 2220/252 20130101;
G11B 2220/2516 20130101; G11B 20/1217 20130101 |
Class at
Publication: |
360/39 ; 360/71;
G9B/15.021; G9B/5.033 |
International
Class: |
G11B 5/09 20060101
G11B005/09; G11B 15/18 20060101 G11B015/18 |
Claims
1. A hard disk drive, comprising: a disk having bit patterned media
with a plurality of data tracks arrayed in architecture pages
having at least one of erase band mode (EBM), shingled mode (SM)
and unallocated space; an actuator having a head for writing data
to the data tracks of the bit patterned media; and a control system
that monitors, reallocates and reconfigures the architecture pages
from EBM, SM or unallocated space to a different one of EBM, SM or
unallocated space to enhance performance of the hard disk
drive.
2. A hard disk drive according to claim 1, wherein each of the
architecture pages comprises a group of adjacent data tracks
spanning one or more sectors.
3. A hard disk drive according to claim 1, wherein a write width of
the head spans at least two data tracks.
4. A hard disk drive according to claim 1, wherein EBM stores data
only on designated data tracks that are located at least a write
width apart from each other, such that data tracks located between
the designated data tracks form unused erase bands and are
re-written every time an adjacent designated data track is written
to.
5. A hard disk drive according to claim 1, wherein SM makes every
data track available to store data and data is written sequentially
on adjacent data tracks in successive order.
6. A hard disk drive according to claim 1, wherein the data tracks
are arrayed in a hypertrack configuration.
7. A hard disk drive according to claim 6, wherein the data tracks
collectively form a rectangular or staggered lattice.
8. A hard disk drive according to claim 6, wherein adjacent ones of
the data tracks are circumferentially offset from each other.
9. A hard disk drive according to claim 6, wherein the data tracks
are grouped and written to in sets of two data tracks such that the
head writes data to both of said two data tracks simultaneously in
a single pass.
10. A hard disk drive according to claim 6, wherein the hypertrack
configuration with EBM has hypertracks that store data and are
spaced apart from adjacent hypertracks by single data tracks that
form unused erase bands.
11. A hard disk drive according to claim 6, wherein the hypertrack
configuration with SM writes only one data track per write
pass.
12. A hard disk drive according to claim 11, wherein SM makes every
data track available to store data and data is written sequentially
on adjacent data tracks in successive order.
13. A hard disk drive according to claim 6, wherein the hypertrack
configuration with SM writes two data tracks write pass.
14. A hard disk drive according to claim 13, wherein the data
tracks are arrayed in a staggered lattice and the head has a low
curvature so that only one bit is written to at a time.
15. A hard disk drive according to claim 13, wherein the data
tracks are arrayed in a rectangular lattice and the head has a high
curvature so that only one bit is written to at a time.
16. A method of partitioning data tracks on a disk of bit patterned
media in a hard disk drive, comprising: providing the disk with
pages having a storage architecture of at least one of erase band
mode (EBM), shingled mode (SM) and empty space; counting an amount
of empty space and a number of EBM pages; assessing if the amount
of empty space is above a selected threshold and, if so, assessing
if any SM pages can be converted to EBM pages; converting SM pages
to EBM pages; updating a status of converted pages and mapping
between a user data location and a physical data location before
returning to the counting step; determining if the number of EBM
pages is sufficient to allow consolidation if the amount of empty
space is not above the selected threshold; consolidating SM pages
and returning to the updating step; consolidating the EBM pages
into SM pages if the number of EBM pages is sufficient to allow
consolidation; and returning to the updating step.
17. A method according to claim 16, further comprising performing
the steps of the method: (a) only if the hard disk drive is idle,
or (b) during a sequence of write operations if the amount of empty
space falls below the selected threshold
18. A method according to claim 16, wherein EBM stores data only on
designated data tracks that are located at least a write width
apart from each other, such that data tracks located between the
designated data tracks form unused erase bands and are re-written
every time an adjacent designated data track is written to.
19. A method according to claim 16, wherein SM makes every data
track available to store data and data is written sequentially on
adjacent data tracks in successive order.
20. A method according to claim 16, wherein the data tracks are
arrayed in a hypertrack configuration such that adjacent ones of
the data tracks are circumferentially offset from each other.
21. A method according to claim 20, wherein the hypertrack
configuration with EBM has hypertracks that store data and are
spaced apart from adjacent hypertracks by single data tracks that
form unused erase bands.
22. A method according to claim 20, wherein the hypertrack
configuration with SM writes only one data track per write pass,
and SM makes every data track available to store data and data is
written sequentially on adjacent data tracks in successive
order.
23. A method according to claim 20, wherein the hypertrack
configuration with SM writes two data tracks write pass, and the
data tracks are arrayed in either (a) a staggered lattice and the
head has a low curvature so that only one bit is written to at a
time, or (b) a rectangular lattice and the head has a high
curvature so that only one bit is written to at a time.
24. A method of partitioning data tracks on a disk of bit patterned
media in a hard disk drive, comprising: organizing the disk into
pages of adjacent data tracks spanning one or more sectors;
partitioning the pages into storage architectures comprising erase
band mode (EBM), shingled mode (SM) and empty space; monitoring
whether the pages are being written to in EBM, SM, or are empty
pages; changing the storage architecture of at least one page based
on how much empty space remains in said at least one page;
converting EBM pages to SM pages when a storage threshold is
exceeded; and transferring valid user data from EBM pages to SM
pages or to empty pages that have been converted to SM pages.
25. A method according to claim 24, further comprising performing
the steps of the method: (a) only if the hard disk drive is idle,
or (b) during a sequence of write operations if an amount of
available disk space falls below a critical threshold
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Disclosure
[0002] This invention generally relates to hard disk drives and, in
particular to an improved system, method and apparatus for storage
architecture for bit patterned media using both erase band and
shingled magnetic recording.
[0003] 2. Description of the Related Art
[0004] Organizing and storing physical data on bit patterned media
(BPM) is a promising candidate for magnetic data storage that
exceeds 1 Tb/in.sup.2. Due to fabrication constraints, high density
BPM will most likely employ data cells that have a bit aspect ratio
(BAR) of 1 to 2. Low BARs pose a challenge to head design, which
favors high BAR. Heads that have the necessary write fields and
write field gradients to write data to BPM with high fidelity tend
to write multiple tracks simultaneously. These types of heads,
however, erase any data than might have been stored on an adjacent
track. The BAR mismatch problem can be solved by using shingled
magnetic recording (SMR). SMR, however, adds complexity and delays
to the recording process. A data storage architecture that reduces
the loss in performance associated with SMR would be desirable.
SUMMARY
[0005] Embodiments of a system, method and apparatus for storage
architecture for bit patterned media using both erase band and
shingled magnetic recording are disclosed. A hard disk drive may
comprise a disk having bit patterned media with a plurality of data
tracks arrayed in architecture pages having at least one of erase
band mode (EBM), shingled mode (SM) and unallocated space. An
actuator has a head for writing data to the data tracks of the bit
patterned media. A control system monitors, reallocates and
reconfigures the architecture pages from EBM, SM or unallocated
space to a different one of EBM, SM or unallocated space to enhance
performance of the hard disk drive.
[0006] In other embodiments, a method of partitioning data tracks
on a disk of bit patterned media in a hard disk drive comprises
providing the disk with pages having a storage architecture of at
least one of erase band mode (EBM), shingled mode (SM) and empty
space; counting an amount of empty space and a number of EBM pages;
assessing if the amount of empty space is above a selected
threshold and, if so, assessing if any SM pages can be converted to
EBM pages; converting SM pages to EBM pages; updating a status of
converted pages and mapping between a user data location and a
physical data location before returning to the counting step;
determining if the number of EBM pages is sufficient to allow
consolidation if the amount of empty space is not above the
selected threshold; consolidating SM pages and returning to the
updating step; consolidating the EBM pages into SM pages if the
number of EBM pages is sufficient to allow consolidation; and
returning to the updating step.
[0007] In another embodiment, a method of partitioning data tracks
on a disk of bit patterned media in a hard disk drive comprises
organizing the disk into pages of adjacent data tracks spanning one
or more sectors; partitioning the pages into storage architectures
comprising erase band mode (EBM), shingled mode (SM) and empty
space; monitoring whether the pages are being written to in EBM,
SM, or are empty pages; changing the storage architecture of at
least one page based on how much empty space remains in said at
least one page; converting EBM pages to SM pages when a storage
threshold is exceeded; and transferring valid user data from EBM
pages to SM pages or to empty pages that have been converted to SM
pages.
[0008] The foregoing and other objects and advantages of these
embodiments will be apparent to those of ordinary skill in the art
in view of the following detailed description, taken in conjunction
with the appended claims and the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] So that the manner in which the features and advantages of
the embodiments are attained and can be understood in more detail,
a more particular description may be had by reference to the
embodiments thereof that are illustrated in the appended drawings.
However, the drawings illustrate only some embodiments and
therefore are not to be considered limiting in scope as there may
be other equally effective embodiments.
[0010] FIGS. 1A and 1B are schematic drawings of embodiments of a
disk with page layouts and states;
[0011] FIG. 2 is a schematic drawing of an embodiment of disk drive
control system;
[0012] FIGS. 3A and 3B are schematic views of embodiments of data
tracks for data storage;
[0013] FIGS. 4A and 4B are schematic views of other embodiments of
data tracks for data storage;
[0014] FIGS. 5A and 5B are schematic views of still other
embodiments of data tracks for data storage;
[0015] FIG. 6 is a high level flow diagram of one embodiment of a
method for data track allocation; and
[0016] FIG. 7 is a schematic diagram of an embodiment of a disk
drive;
[0017] The use of the same reference symbols in different drawings
indicates similar or identical items.
DETAILED DESCRIPTION
[0018] FIGS. 1-7 disclose embodiments of a system, method and
apparatus for storage architecture for bit patterned media using
both erase band and shingled magnetic recording. The data storage
architecture writes and stores data on a bit patterned media disk
in which the write width of the write head may span two or more
tracks. The wide write head can write each of the written tracks
with high fidelity, though with duplicate data in some embodiments.
Embodiments for the patterned islands of media are collectively
arrayed in rectangular, staggered, parallelogram and other
lattices.
[0019] The data may be recorded or written using one of two
techniques, including an erase band mode (EBM) and a shingled mode
(SM). Data storage regions on the disk (e.g., tracks and sectors)
may be grouped into units or pages. For example, FIG. 1A
illustrates a disk 111 having data sectors in between servo
sections 112 with an EBM page 121 and a SM page 123. Each of these
data storage regions is arranged in a circumferential band around
the disk. Each page comprises a group of adjacent tracks within a
sector 112 or groups of sectors 112 on the disk 111. Though FIG. 1A
shows each page extending around the entire disk, the grouping of
tracks into pages may be performed in many different ways. As
depicted in FIG. 1B, the pages may comprise smaller groupings of
tracks even within a data sector. The disk drive monitors whether a
page is being used for a state of EBM writing 121, SM writing 123,
or is an empty, unallocated page 125. The designation of a page to
either EBM or SM is not fixed and can be changed. For example, the
pages may be switched by considering how much free space remains in
each type of page.
[0020] For example, FIG. 2 depicts a high level schematic diagram
of an embodiment of drive electronics for monitoring the allocation
of pages. Control circuitry 116 includes motion control electronics
118 and read/write electronics 120 for operating voice coil motor
(VCM) 122 and read/write head 110, respectively. Operating system
124 communicates read/write requests and data
validation/invalidation to a page tracking module 126, which also
communicates with control circuitry 116. In some embodiments, page
tracking module 126 provides a page allocation module 128, and
customer track to physical track location mapping 130.
[0021] In EBM, data is stored only on tracks that are located at
least a write width apart so that they are not corrupted when
nearby data tracks are written. The tracks located between the
designated data tracks form `permanent` unused spaces or "erase
bands" and are re-written every time an adjacent data track is
written to.
[0022] With SM or the second type of write mode, every track may be
used to store data and are written using shingling magnetic
recording. In SM, groups of adjacent tracks are written in
successive passes with the head translated by one physical track
width after each pass. See, e.g., U.S. Pat. App. Pub. 2002/0071198,
which is incorporated herein by reference in its entirety.
[0023] Reconfiguring a page from EBM to SM causes the erase bands
of EBM to become usable data storage tracks in SM. Similarly,
changing a page from SM to EBM reduces half of the data tracks to
erase bands. Thus, while EBM allows for quicker writing and simpler
storage architecture, it has a lower effective storage density than
SM. To improve performance, the disk drive may dynamically allocate
the partitioning of physical storage space into either EBM or
SM.
[0024] For example, the storage architecture may be employed in a
head-media system in which the write head writes three tracks
simultaneously, with a bit aspect ratio or BAR of about 1 to 2. The
extension of this example to systems in which the write width
writes any number of multiple tracks and arbitrary BAR follows
easily from this example.
[0025] Referring to FIGS. 3A and 3B, embodiments of the two write
modes (i.e., EBM and SM, respectively) are depicted for writing
user data to the physical bits or islands on a magnetic media disk
in a hard disk drive using an exemplary three-track wide write head
20. Again, heads having different widths are equally suitable. Head
20 moves left to right in a longitudinal direction, as indicated by
the arrow. In EBM, there are two types of tracks of islands formed
in an alternating pattern: data tracks 21, 25, 27, and erase bands
or tracks 23, 24, 28, 29. User data is stored only in the data
tracks. The tracks immediately adjacent to or in between the data
tracks are unused space and denoted as the erase bands. For
example, the two adjacent erase bands 23, 24 on the lateral sides
of the "new data" user data track 21 are overwritten every time
data is written to data track 21. Also shown are data tracks 25, 27
wherein data was previously written. These data tracks 25, 27 may
be referred to as storing `old data.` Data track 25 has adjacent
erase bands 23, 28, while data track 27 has adjacent erase bands
24, 29. The EBM architecture has the disadvantage of reducing the
effective storage area by about half, but suffers no performance
loss in comparison to SM.
[0026] In the embodiment of SM depicted in FIG. 3B, data is written
to every physical track in a shingled fashion. Thus, SM has no
erase bands but only unused space. For example, the user data is
written starting with the bottom track 31 and successively to each
adjacent track from bottom to top. In the illustrated embodiment,
data tracks 31, 33 were written to prior to track 35, which
represents `new data.` Tracks 37 are merely unused space that has
not yet been written to in SM. In addition, the position of the
head 20 with respect to the track centers may need to be adjusted
slightly between the SM and EBM write modes.
[0027] FIGS. 4A and 4B depict embodiments of EBM and SM
architecture as applied to an application having hypertrack
recording on a staggered lattice (e.g., triangular, parallelogram,
etc.) of islands. See, e.g., U.S. Pat. App. Pub. 2008/0204915,
which is incorporated herein by reference in its entirety. In
hypertrack recording, the user data is grouped and written on two
data tracks 41, 42 and the write head 20 writes data to both tracks
41, 42 simultaneously in a single pass. Although the example shows
the hypertracks 40 in groups of two data tracks, other groupings
may be employed to match the track layout to the width of the
recording head.
[0028] When hypertrack recording is configured with an EBM
architecture, the hypertracks that store user data are spaced by
"half" of a hypertrack (i.e., one physical row or track of bits)
for a head whose write width spans two hypertracks. The half-tracks
43, 44 serve as erase bands as described herein for other
embodiments. Other hypertracks 40 comprising other data tracks 41,
42 and other erase bands 43, 44 also are shown. However,
hypertracks with SM architecture can be configured in two different
ways, depending on the head field properties at the edge of the
write head. The basic mode is shown in FIG. 4B, in which only one
track 51 (i.e., one half of a hypertrack) is written to per write
pass. As described for other embodiments, SM writes data to every
physical track in a shingled fashion so there are no erase bands,
only unused space. For example, data may be written starting with
the bottom track 52 and successively to each adjacent track 53, 54
from bottom to top. Thus, data tracks 52, 53, 54 were written to
prior to track 51, which represents new data. Tracks 57 are unused
data space that has not yet been written to in SM.
[0029] In some head-media systems (FIGS. 5A and 5B), a second type
of shingled recording process may be employed in which two data
tracks 61, 62 (i.e., a whole hyper track 60) are written to per
pass. The ability of the head 20 to write two tracks 61, 62 per
pass depends on the head field curvature and write misregistration
margins. For example, hypertrack shingled mode writing on a
staggered lattice (FIG. 5A) may be performed using a low curvature
or substantially rectangular head 20. However, the head 20 of FIG.
5B has a higher curvature at taper 63 to perform hypertrack
shingled mode writing on a rectangular lattice. Like other SM
embodiments, these examples include old data tracks 65 and tracks
67 of unused space. The cross-track position of the head with
respect to the written tracks may be adjusted appropriately to
improve write fidelity.
[0030] FIG. 6 depicts an embodiment of a method for partitioning
the tracks of useable storage space on a BPM disk into EBM and/or
SM writing architectures. Physically, there is no difference
between tracks used for each mode, and all tracks can be used for
either mode. The disk drive need only account for how the disk
space has been partitioned.
[0031] In some embodiments, data storage regions on the disk are
grouped into units or pages as described previously herein for
FIGS. 1A and 1B. The designation of a page to either EBM or SM is
not fixed and can be changed. For example, the pages may be
switched by considering how much free space remains in each type of
page. In one embodiment, the disk drive considers how many empty
pages remain on the drive. Once the number falls below a threshold,
the drive starts converting EBM pages to SM pages. The conversion
may include transferring valid user data in the EBM pages to
existing SM pages or new empty pages that have been converted to SM
pages. The specific SMR protocol for writing data to SM pages may
vary. The empty EBM pages are designated as empty pages. The
process may continue until the number of empty pages exceeds a
predefined threshold.
[0032] In the example of FIG. 6, the method starts by inquiring
whether the drive is idle (step 70) and, if so, the amount of empty
space and number of EBM pages are counted (step 71). In this
embodiment, the process does not reallocate pages if the drive is
not idle. In other embodiments, however, the drive may perform
these steps when it is not idle. For example, the method may occur
during a sequence of write operations if the amount of available
disk space falls below a critical threshold. If the amount of empty
space is above a selected threshold (step 73), the drive assesses
if the SM pages can be converted to EBM pages (step 75). If so,
they are converted (step 77) and the status of the altered pages is
updated (step 79). The method also updates mapping between user
data location and the physical data location (step 81) before
returning to step 71.
[0033] If the amount of empty space is not above a selected
threshold (step 73), the method determines if the number of EBM
pages is sufficient to allow consolidation (step 83). If not, the
method determines if the SM pages can be consolidated (step 85) and
consolidates them (step 87) if so, before returning to the updating
step 79. If the number of EBM pages is sufficient to allow
consolidation (step 83), the EBM pages are consolidated into SM
pages (step 89), and the method returns to the updating step
79.
[0034] FIG. 7 depicts a schematic diagram of an embodiment of a
hard disk drive assembly 100. The hard disk drive assembly 100
generally comprises a housing or enclosure with one or more disks
as described herein. The disk comprises magnetic recording media
111, rotated at high speeds by a spindle motor (not shown) during
operation. The concentric data tracks 113 are formed on either or
both disk surfaces magnetically to receive and store
information.
[0035] Embodiments of a read or read/write head 110 may be moved
across the disk surface by an actuator assembly 106, allowing the
head 110 to read or write magnetic data to a particular track 113.
The actuator assembly 106 may pivot on a pivot 114. The actuator
assembly 106 may form part of a closed loop feedback system, known
as servo control, which dynamically positions the read/write head
110 to compensate for thermal expansion of the magnetic recording
media 111 as well as vibrations and other disturbances. Also
involved in the servo control system is a complex computational
algorithm executed by a microprocessor, digital signal processor,
or analog signal processor 116 that receives data address
information from a computer, converts it to a location on the media
111, and moves the read/write head 110 accordingly.
[0036] In some embodiments of hard disk drive systems, read/write
heads 110 periodically reference servo patterns recorded on the
disk to ensure accurate head 110 positioning. Servo patterns may be
used to ensure a read/write head 110 follows a particular track
accurately, and to control and monitor transition of the head 110
from one track 113 to another. Upon referencing a servo pattern,
the read/write head 110 obtains head position information that
enables the control circuitry 116 to subsequently realign the head
110 to correct any detected error.
[0037] Servo patterns may be contained in engineered servo sections
112 embedded within a plurality of data tracks 113 to allow
frequent sampling of the servo patterns for improved disk drive
performance, in some embodiments. In a typical magnetic recording
media 111, embedded servo sections 112 extend substantially
radially from the center of the magnetic recording media 111, like
spokes from the center of a wheel. Unlike spokes however, servo
sections 112 form a subtle, arc-shaped path calibrated to
substantially match the range of motion of the read/write head
110.
[0038] In other embodiments, a hard disk drive comprises a disk
having bit patterned media with a plurality of data tracks arrayed
in architecture pages having at least one of erase band mode (EBM),
shingled mode (SM) and unallocated space. An actuator has a head
for writing data to the data tracks of the bit patterned media. A
control system monitors, reallocates and reconfigures the
architecture pages from EBM, SM or unallocated space to a different
one of EBM, SM or unallocated space to enhance performance of the
hard disk drive. Each of the architecture pages may comprise a
group of adjacent data tracks spanning one or more sectors, and a
write width of the head may span at least two data tracks.
[0039] In some embodiments, EBM stores data only on designated data
tracks that are located at least a write width apart from each
other, such that data tracks located between the designated data
tracks form unused erase bands and are re-written every time an
adjacent designated data track is written to. SM may make every
data track available to store data and data is written sequentially
on adjacent data tracks in successive order.
[0040] In other embodiments, the data tracks are arrayed in a
hypertrack configuration, such as a rectangular or staggered
lattice. Adjacent ones of the data tracks may be circumferentially
offset from each other. The data tracks may be grouped and written
to in sets of two data tracks such that the head writes data to
both of said two data tracks simultaneously in a single pass. The
hypertrack configuration with EBM may have hypertracks that store
data and are spaced apart from adjacent hypertracks by single data
tracks that form unused erase bands. The hypertrack configuration
with SM may write only one data track per write pass. SM may make
every data track available to store data and data is written
sequentially on adjacent data tracks in successive order. The
hypertrack configuration with SM may write two data tracks write
pass. The data tracks may be arrayed in a staggered lattice and the
head has a low curvature so that only one bit is written to at a
time. The data tracks also may be arrayed in a rectangular lattice
and the head has a high curvature so that only one bit is written
to at a time.
[0041] In still other embodiments, a method of partitioning data
tracks on a disk of bit patterned media in a hard disk drive
comprises providing the disk with pages having a storage
architecture of at least one of erase band mode (EBM), shingled
mode (SM) and empty space; counting an amount of empty space and a
number of EBM pages; assessing if the amount of empty space is
above a selected threshold and, if so, assessing if any SM pages
can be converted to EBM pages; converting SM pages to EBM pages;
updating a status of converted pages and mapping between a user
data location and a physical data location before returning to the
counting step; determining if the number of EBM pages is sufficient
to allow consolidation if the amount of empty space is not above
the selected threshold; consolidating SM pages and returning to the
updating step; consolidating the EBM pages into SM pages if the
number of EBM pages is sufficient to allow consolidation; and
returning to the updating step. These steps may be performed when
the hard disk drive is idle or during writing operations. Other
embodiments may comprise other steps, features and elements
previously described herein.
[0042] In still another embodiment, a method of partitioning data
tracks on a disk of bit patterned media in a hard disk drive
comprises organizing the disk into pages of adjacent data tracks
spanning one or more sectors; partitioning the pages into storage
architectures comprising erase band mode (EBM), shingled mode (SM)
and empty space; monitoring whether the pages are being written to
in EBM, SM, or are empty pages; changing the storage architecture
of at least one page based on how much empty space remains in said
at least one page; converting EBM pages to SM pages when a storage
threshold is exceeded; and transferring valid user data from EBM
pages to SM pages or to empty pages that have been converted to SM
pages.
[0043] This written description uses examples to disclose the
embodiments, including the best mode, and also to enable those of
ordinary skill in the art to make and use the invention. The
patentable scope is defined by the claims, and may include other
examples that occur to those skilled in the art. Such other
examples are intended to be within the scope of the claims if they
have structural elements that do not differ from the literal
language of the claims, or if they include equivalent structural
elements with insubstantial differences from the literal languages
of the claims.
[0044] Note that not all of the activities described above in the
general description or the examples are required, that a portion of
a specific activity may not be required, and that one or more
further activities may be performed in addition to those described.
The order in which activities are listed are not necessarily the
order in which they are performed.
[0045] In the foregoing specification, the concepts have been
described with reference to specific embodiments. However, one of
ordinary skill in the art appreciates that various modifications
and changes can be made without departing from the scope of the
invention as set forth in the claims below. Accordingly, the
specification and figures are to be regarded in an illustrative
rather than a restrictive sense, and all such modifications are
intended to be included within the scope of invention.
[0046] As used herein, the terms "comprises," "comprising,"
"includes," "including," "has," "having" or any other variation
thereof, are intended to cover a non-exclusive inclusion. For
example, a process, method, article, or apparatus that comprises a
list of features is not necessarily limited only to those features
but may include other features not expressly listed or inherent to
such process, method, article, or apparatus. Further, unless
expressly stated to the contrary, "or" refers to an inclusive-or
and not to an exclusive-or. For example, a condition A or B is
satisfied by any one of the following: A is true (or present) and B
is false (or not present), A is false (or not present) and B is
true (or present), and both A and B are true (or present).
[0047] Also, the use of "a" or "an" are employed to describe
elements and components described herein. This is done merely for
convenience and to give a general sense of the scope of the
invention. This description should be read to include one or at
least one and the singular also includes the plural unless it is
obvious that it is meant otherwise.
[0048] Benefits, other advantages, and solutions to problems have
been described above with regard to specific embodiments. However,
the benefits, advantages, solutions to problems, and any feature(s)
that may cause any benefit, advantage, or solution to occur or
become more pronounced are not to be construed as a critical,
required, or essential feature of any or all the claims.
[0049] After reading the specification, skilled artisans will
appreciate that certain features are, for clarity, described herein
in the context of separate embodiments, may also be provided in
combination in a single embodiment. Conversely, various features
that are, for brevity, described in the context of a single
embodiment, may also be provided separately or in any
subcombination. Further, references to values stated in ranges
include each and every value within that range.
* * * * *